Sanaa, Yemen — Yemen's vulnerability as a potential militant haven has been underscored by four attacks on security forces in eight days, as the country battles a Shiite rebellion in the north and a secessionist movement in the south.

The conflict in the north drew international attention last month, when the central government blamed the Shiite rebels – known as Houthis – for the June 12 kidnapping of nine foreigners, including two German women and a South Korean woman who turned up dead two days later.

Houthi leadership strenuously denied involvement, and the group has no history of killing foreign nationals.

Tensions in the wake of the murders could lead to a fresh round of fighting in the conflict – an ongoing battle in the northern Saada governate between the government and Houthi rebels that has claimed hundreds of lives and displaced more than 100,000.

"One week ago, the authorities sent soldiers to Saada and attacked the governorate's citizens," said a senior Houthi rebel in a phone interview shortly after the kidnappings. "There were clashes between the Houthis and soldiers in the region."

An intensifying of the Saada conflict – one of numerous problems plaguing Yemen's fragile unity – could severely undermine the country, one of the poorest in the Arab world, says Joost R. Hiltermann of the International Crisis Group (ICG).

"With secessionist sentiments on the rise in the south and an escalating threat from Al Qaeda, another round in the north could prove devastating to a country with a weak-to-failing state system," says Mr. Hiltermann, the ICG's deputy program director of the Middle East and North Africa division.

The Yemeni and Saudi branches of Al Qaeda merged in January this year, prompting the US Director of National Intelligence to say that Yemen was "reemerging as a jihadist battleground and potential regional base of operations for Al Qaeda."

Yemen paints rebels as Islamic extremists

Yemen's government has attempted to garner international support for its fight against the Houthis by linking its efforts to the fight against radical Islam, says a recent ICG report, "Yemen: Defusing the Saada Time Bomb." The government has accused the rebels of plotting to attack Western interests, kidnap foreign diplomats, and attack unveiled women.

Such accusations – including the government's blaming of Houthis for the June kidnappings – are inaccurate, says Sheila Carapico, author of "Civil Society in Yemen."

"Early in the Saada conflict, the government tried to falsely portray its campaign against the Believing Youth as part of the global war on terrorism, whereas the Houthi movement is anti-Wahabbi and, if anything, opposes Al Qaeda," says Professor Carapico, who teaches international relations at the University of Richmond in Virginia.

Still, the conflict has been largely ignored by the international community, says the ICG report.

Quantifying civilian suffering in the Saada war is impossible because the government restricts access to conflict zones for the press and many foreign aid organizations. Yemeni media are prohibited from covering the conflict, and in the past, local journalists have been arrested for breaking these media restrictions.

Origins of the Saada conflict

Violent confrontations originally erupted between the Yemeni forces and the Houthis in 2004, when the government sought to quell a militant movement gaining popularity in Saada, known then as the Believing Youth. Among its grievances was the Yemeni government's close relationship with the United States.

Yemeni forces killed rebel leader Hussein al-Houthi in September 2004. But instead of bringing a halt to the violence, Mr. Houthi's death contributed to the rebels' narrative that their distinct culture as followers of the Zaydi branch of Shiite Islam was under attack by Yemen's central government. Fighting in the region has continued to flare up over the past five years.

On July 6, a court sentenced seven Houthi rebels to death for their role in a deadly battle with security forces near Sanaa last year.

The government claims that Houthis are a threat to the Yemeni state, which is primarily Sunni, because their goal is to restore the Zaydi imamate in Saada Province that was dissolved in 1962. The government also accuses the rebels of receiving support from Iran.

While Saada was the last region of Yemen to remain loyal to the imamate in the 1960s, the rebels themselves deny that this is their goal, says Carapico.

The conflict has also become much more complex since its early days, says Hiltermann.

"The Saada war has metastasized from its humble ideological beginnings into a conflict involving an array of actors fighting for a series of different, mostly material, reasons," he says.